A historic treasure trove of archival letters and notes belonging to “sheroic” writer and poet Maya Angelou has been acquired by the Schomburg Center for Research in Black Culture in Harlem.

The cache of more than 340 boxes includes correspondence with writers such as Langston Hughes and James Baldwin, photographer Gordon Parks and civil rights leader Martin Luther King.

Watch Maya Angelou read 'On the Pulse of Morning'
Maya Angelou is perhaps best known for her reading at Bill Clinton's 1992 inauguration. "Lift up your eyes / The day is breaking for you," Angelou read.

“I’ve been planning this for many years,” said Angelou, 82, who resides part time in a townhouse in Harlem. The Schomburg, which Angelou has lauded as a repository of the victories and the losses of the African American experience, “was always the destination,” the Pulitzer Prize nominee said Wednesday.

Angelou relinquished her papers for a cost that she estimates is “one-twentieth of what I could have gotten had I chosen to sell them, but I wanted to make them accessible ... to anyone who wants to know about African American culture and about the United States at a certain point in time.”

In one of the letters, Malcolm X urges Angelou to help him bring the issue of racism and sexism in the U.S. before the United Nations.

“I told him I didn’t know if I could be of use. He said my head might be in the stars, but my feet are always planted in the earth,” Angelou recounted with a laugh.

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Notes for Angelou’s most famous book, “I Know Why the Caged Bird Sings,” and many of her poems, are also included, as are drafts of the poem she wrote for President Bill Clinton’s inauguration, “On the Pulse of Morning,” at his request.

The cache reveals Angelou as a counselor and inspiration to major leaders and change agents in the tumultuous civil rights era, said Bernice Green, spokeswoman for the Schomburg Center. It will take employees at least two years to properly archive the documents, which were purchased with the assistance of an anonymous donor, Green said.

The Schomburg plans to mount a small display for the public in the interim.